American Persimmon Dormancy Requirements

forestandfarmAugust 29, 2013

I started a boat load of 90 chromosome American persimmons from seed this summer in rootmaker cells. These are for wildlife and most will be planted directly from the cells into the field this fall. Eventually they will be used as rootstook for bark grafting specific varieties.

However, I want to try my hand at bench grafting so I transplanted about 45 of them into 1 gallon Rootbuilder II pots. I plan to overwinter these and attempt to bench graft them next spring.

My concern is size. Some may not be large enough for bench grafting by the appropriate time next spring if I let nature take its course.

I'm considering letting them go dormant naturally outside, but bringing them inside and giving them a head-start growing under lights. I'm hoping this will let them bulk up a bit before grafting time.

Does anyone know how much dormancy (Chill hours or something) they require before I wake them up?

I'm not sure but think that American persimmon are like Asians. They have a low chilling requirement and break dormancy based on heat units. Pecans, figs, and grapes fall in the same category. Low chilling requirement but high heat requirements to leaf out. Thus they leaf out late but are very freeze sensitive, both foliage and flowers, after leafing out.

Based on that in zone 7 they will get enough dormancy by the first of the year. Pull them inside after that and pile on the heat units to break them out of dormancy.

That's what I'd do. When I lived in Amarillo 400 miles north of here, zone 6-7, I felt all crops had enough chilling by sometime in January. Chilling during the early part of dormancy is the most effective. Those persimmon will be ready to go by Jan 1.

All zone 7 climates aren't the same. Out east zone 7 gets more chilling than Amarillo. The more clouds the better as long as it's not constantly below freezing. 40-45F is the most effective. Four weeks at constant 40F and they'd be ready, probably even two weeks at 40F after they drop their leaves.